These are two of my favorite knightly virtues because people so often ignore them.
Courtesy, however, was essential in a culture that placed a high value on mutual love and earning the favor of a lady (as opposed to just abducting or buying her). Furthermore, courtesy in the High Middle Ages was also expected of young people when addressing their elders and of people of lower rank when addressing their superiors. Indeed, courtesy as an ideal was supposed to regulate communications between all people of "worth" in the Age of Chivalry, and a mastery of courtesy was demanded of children and admired in adults.
As for cleanliness, many people nowadays still imagine that people in the Middle Ages did not place a value on cleanliness and even abhorred it. The fact that people did not bathe frequently in the 18th century is extrapolated backwards, and I’ve read far too many books set in the crusades that portray the Muslims as clean and the Christians as filthy and stinking. Not true.
Bathing was much more difficult when water did not come running hot and cold out of a tap, but that if anything made it more valued. It was an important ritual of knighthood itself, and is frequently portrayed in medieval manuscripts. The rich had private baths, and the poor went to bath houses. In the hotter climate of southern Europe, from Spain to Greece, where the Romans had built large bath houses, the tradition continued particularly strong, and in the crusader kingdoms baths were built in the Turkish tradition – by Christians.
In fact, many pilgrims who came to the crusader kingdoms, were initially shocked by the extent to which the local population “indulged” in the pleasures of these bathhouses. The objection, however, was not to the concept of cleanliness but rather to the associated pleasures of massages and scented oils and the ambiance.
As a renowned diplomat, capable of intermediating between Tripoli and Lusignan and negotiating on multiple occasions with Saladin, Balian would have had to have at the least a diplomatic manner and a courteous tongue. Admittedly, diplomacy isn't all about nice words, but it has been defined as "the ability to tell someone to go to hell in such a way that they look forward to the trip." I think we can assume, therefore, that Balian had mastered the virtue of courtesy to a high degree. As for cleanliness, since Balian was one of the “local” lords, born in the Holy Land, we can assume he was a frequent visitor to bath houses. He, more than most knights in the west at this time, would have fulfilled the knightly virtue of “cleanliness.”